31231212 has 24 divisors (see below), whose sum is σ = 76708800. Its totient is φ = 9862416.

The previous prime is 31231139. The next prime is 31231223. The reversal of 31231212 is 21213213.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 31231191 and 31231200.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68262 + ... + 68717.

It is an arithmetic number, because the mean of its divisors is an integer number (3196200).

Almost surely, 2^31231212 is an apocalyptic number.

It is an amenable number.

31231212 is an abundant number, since it is smaller than the sum of its proper divisors (45477588).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31231212 is a wasteful number, since it uses less digits than its factorization.

31231212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137005 (or 137003 counting only the distinct ones).

The product of its digits is 72, while the sum is 15.

The square root of 31231212 is about 5588.4892412887. The cubic root of 31231212 is about 314.9171260947.

Adding to 31231212 its reverse (21213213), we get a palindrome (52444425).

The spelling of 31231212 in words is "thirty-one million, two hundred thirty-one thousand, two hundred twelve".